Portable cooler



FIG. 1 is a front elevational view of a portable cooler incorporating my new design;

FIG. 2 is a back elevational view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a portable cooler, as shown and described. 